What are functions ? From an introduction of the basic concepts of functions to more advanced functions met in economics, engineering and the sciences, these topics provide an excellent foundation for undergraduate study.

# Trigonometric functions

The sine, cosine and tangent of an angle are all defined in terms of trigonometry, but they can also be expressed as functions. How to restrict the domain of each function in order to define an inverse function is also described. Video tutorial 25 mins.